Hybrid SNCR/In Hybrid SNCR/In - - Duct SCR Duct SCR System System Dale Pfaff Dale Pfaff FUEL TECH, INC. FUEL TECH, INC. Batavia, IL Batavia, IL Rich Abrams Rich Abrams BABCOCK POWER ENVIRONMENTAL BABCOCK POWER ENVIRONMENTAL Worcester, MA Worcester, MA Environmental Controls Conference – Pittsburgh, PA May 16 – 18, 2006
22
Embed
Hybrid SNCR/In-Duct SCR System · Hybrid SNCR/In-Duct SCR System Dale Pfaff FUEL TECH, INC. ... Hybrid NO x Control System ... • 1:40 scale flow model
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Hybrid GoalsHybrid GoalsReal Life ExamplesReal Life ExamplesCostsCosts
Hybrid NOHybrid NOxx Control SystemControl System““CascadeCascade®®””
STEAM TURBINE
AIR
PREHEATER(S)
ECONOMIZER
BYPASS
IN-DUCT SCR
PULVERIZER(S)
BOILER
PRIMARY AIR
CATALYST
COAL
ECONOMIZER
LOW NOx BURNERS
SNCR
SNCR
AIR
UREA
STORAGE
RedesignedRedesigned SNCR SNCR System with SCR System with SCR (using urea)(using urea)Higher NOHigher NOxxReduction and Reduction and Utilization than Utilization than SNCRSNCRNHNH33 slip consumedslip consumedin SCR in SCR Low SOLow SO22 to SOto SO33Conversion RatesConversion Rates50 50 -- 75% overall 75% overall NONOxx reductionreductionLow capital costsLow capital costs
Traditional Urea Based Traditional Urea Based SSelective elective NNonon--CCatalytic atalytic RReduction (SNCR) of NOxeduction (SNCR) of NOx
Primary Combustion
NOx
NOxOUT AUrea
Reagent
1,700 -2,400 ° F
N2/H2O/CO2 (NH3 Slip)
Post CombustionPost CombustionGas Phase ReactionGas Phase ReactionFurnace is the ReactorFurnace is the ReactorTypical Combustion ProductsTypical Combustion ProductsProcess ParametersProcess Parameters•• TimeTime•• Temperature and SpeciesTemperature and Species•• Distribution Distribution
Cold Flow Models and Flue Gas MixingCold Flow Models and Flue Gas Mixing
•• 1:40 scale flow model1:40 scale flow model
BPI makes extensive use of flow modeling to guide BPI makes extensive use of flow modeling to guide designs and to ensure proper distributiondesigns and to ensure proper distribution
Delta Wing MixerDelta Wing Mixer
Typical Hybrid Process GoalsTypical Hybrid Process GoalsMultiple Levels of SNCR Injection for Multiple Levels of SNCR Injection for Load Following CapabilitiesLoad Following Capabilities50 50 -- 75% Overall NOx Reduction, 2 75% Overall NOx Reduction, 2 -- 5 5 ppm NHppm NH33 SlipSlipOne Catalyst Layer at 1.3 m DepthOne Catalyst Layer at 1.3 m DepthSCR Inlet Temp = 650 SCR Inlet Temp = 650 °°F Norm / 800 F Norm / 800 °°F F MaxMaxNo Ammonia Injection GridNo Ammonia Injection GridEfficient Mixing to Achieve Uniform Efficient Mixing to Achieve Uniform DistributionDistributionSOSO22 to SOto SO33 Conversion < 0.5 %Conversion < 0.5 %Fits within the Physical Space LimitationsFits within the Physical Space Limitations
Commercial Compact SCR and Hybrid (SNCR/SCR)
Examples
Example 1: Example 1: Compact InCompact In--Duct SCR Duct SCR Exelon Handley Unit 3Exelon Handley Unit 3
Turbo Boiler Turbo Boiler –– Gas Gas FiredFired
94% NOx Removal 94% NOx Removal SCRSCR
InIn--duct Reactorduct Reactor
Delta Wing Mixing Delta Wing Mixing SystemSystem
Honeycomb CatalystHoneycomb Catalyst
BPI BPI -- Handley Test ResultsHandley Test ResultsFull load and low load NOx outlet Full load and low load NOx outlet concentrations achieved at 0.02 and concentrations achieved at 0.02 and 0.01 lbs/Mmbtu respectively0.01 lbs/Mmbtu respectively
NOx removal efficiencies of >94% NOx removal efficiencies of >94%
•• Ammonia Slip at 10 Ammonia Slip at 10 ppmppm or lessor less
Example 3; High Load (320MWe) Hybrid Example 3; High Load (320MWe) Hybrid ResultsResults
Example 4; AES Example 4; AES GreenidgeGreenidge Application Application Hybrid SystemHybrid System
115 MW Coal Fired Unit, 2.9% S 115 MW Coal Fired Unit, 2.9% S Bituminous coalBituminous coalTwo levels of SNCRTwo levels of SNCRInIn--duct reactor; single layer of catalystduct reactor; single layer of catalystShort distance between economizer and Short distance between economizer and reactorreactorSNCR provides ~ 40% reductionSNCR provides ~ 40% reductionSCR provides balanceSCR provides balanceOverall system provides ~ 66% Overall system provides ~ 66% reductionreduction
Hybrid combines redesigned SNCR with SCRHybrid combines redesigned SNCR with SCR
Control Flexibility: Operating vs. Capital Control Flexibility: Operating vs. Capital CostsCosts
Hybrid can control slip and improve Hybrid can control slip and improve utilizationutilization
50% and 75% NOx Reduction with 50% and 75% NOx Reduction with significantly reduced SCR retrofit capitalsignificantly reduced SCR retrofit capital
Each Unit Must Be Evaluated to Determine Each Unit Must Be Evaluated to Determine Feasibility for placement of an INFeasibility for placement of an IN--DUCT or DUCT or COMPACT SCR.COMPACT SCR.
2 Utility and 3 Industrial Hybrid Applications2 Utility and 3 Industrial Hybrid Applications